1. Field of the Invention
This invention relates generally to surgical instrumentation and, more particularly, to a surgical retractor having deployable blades for use with endoscopic or laparoscopic devices in performing examinations or surgical procedures within body cavities.
2. Description of Related Art
Most endoscopic or laparoscopic procedures are characterized by the provision of an elongated cannula structure having a relatively thin diameter with a proximal and distal end. The distal end is passed through the surrounding tissue into the body cavity wherein the surgical procedure or examination is to be effected, thus providing a conduit for the insertion of surgical instrumentation. A plurality of cannula structures may be used to allow operation of a variety of instruments simultaneously during a given procedure.
In conventional surgical procedures the function of holding tissue and organs in a given location to facilitate access and viewing is typically accomplished by a retractor. This instrumentation is ordinarily in the form of a broad paddle structure or multiple fingers attached to a handle. See, for example, U.S. Pat. No. 3,467,079 (James). This structure, however, is not usable in endoscopic procedures because the retractor is too large to be insertable through the cannula structure into the operative body cavity.
Collapsible intralumen expanders or retractors have taken the form of radial fingers which are activatable to extend relative to each other upon entering the body cavity. See, for example, U.S. Pat. Nos. 4,654,028 (Suma), 4,459,978 (Kotsanis). Dilators of this type are also known. See, for example, U.S. Pat. Nos. 1,328,624 (Graham) and 972,983 (Arthur). In each case, once the retractive or dilatory function is completed, the fingers are compressed and withdrawn. Another collapsible retractor structure includes a pair of collapsible fingers joined by a web of resilient material which, upon insertion into the cannula structure, can expand to form a retractive structure. See, for example, U.S. Pat. No. 4,190,042 (Sinnreich).
Greatly improved retractor structure has been developed and is described in commonly assigned co-pending patent application Ser. No. 07/634,482 filed Dec. 27, 1990. That structure shows a plurality of interleaved retractor blades mounted in a tubular housing. The blades are movable between a closed position and an open position to facilitate ease of insertion and deployment through a cannula. Other surgical apparatus having deployable interleaved retractor blades have been described in Soviet references. See, for example, SU 736-949 (MOME) which describes an instrument having an elongated housing with a plurality of blades operative at one end by means of a manipulator at the opposed end, and SU 1360-708-A (MEDI) which describes an instrument having a plurality of interleaved blades which cannot be manipulated at a distance and thus is unsuited for performing endoscopic or laparoscopic procedures.